I now have iSCSI working, and have managed to resolve the problems I was having in my previous post. The problem was caused by me trying to use the wrong syntax in iscsiadm, the command in open-iscsi that you use to manage iscsi on your Linux system.
If you try to login to an iscsi target using iscsiadm with the following syntax, it locks up your Linux system. While it is my fault I was using the incorrect syntax, a sane tool should not be able to hang an entire system just because the user uses the wrong syntax with the command, obviously. This command causes the crash:
iscsiadm -m node -p 10.0.0.1:3260 --targetname target --login
Note that the
--targetname parameter is supposed to have an equals sign between the switch and the parameter, and I was forgetting the equals sign in favour of a space. The proper command would be this:
iscsiadm -m node -p 10.0.0.1:3260 --targetname=target --login
I have fixed my scripts and now iscsi is working for me on Linux initiators, and I have also submitted this as a bug to the open-iscsi mailing list, so that in the future, other dummies won’t crash their servers because of a typo. Check the link to see if any discussion develops on the bug report.
Since VMworld, and all the talk I heard there about iSCSI, I’ve become interested in learning more about iSCSI in the various environments we use at work. To that end, I’ve set up an iSCSI target on our Solaris-based x4500 (because with zfs zvols, iSCSI targets are pretty trivial to set up). I’ve been trying to get various software initiators to talk to it. Here’s my track record so far:
- A physical machine running OpenSUSE Linux 10.2 with open-iscsi: discovery works, but logging into the iscsi portal on the x4500 locks up the OpenSUSE box completely, forcing a power-off reboot.
- A VMware Server VM running Solaris Express DE: just works.
- A VMware Server VM running Windows XP with the Microsoft iSCSI initiator: just works.
- A physical machine running Ubuntu 7.04 with open-iscsi: discovery works, but logging into the iscsi portal locks the box up completely forcing a power-off reboot.
- Netware: just works.
Conclusion: Either find out what’s wrong with open-iscsi on my versions of the Linux kernel or the conflict between open-iscsi and Solaris’s iscsi target, or find another iscsi tool chain on Linux.
I got back from VMworld last Friday. I had intended to blog throughout the sessions as I have in the past with Brainshare, but unfortunately the internet connectivity in the presentation rooms at the Moscone Center was not good enough to maintain a decent connection. I suppose I could have done offline blog posts and then uploaded them during breaks, but it was too much fiddling and I didn’t bother.
However, there was lots of great information at the conference. I learned some immediately applicable information about securing ESX servers and services that run on VMware servers. I also learned some practical stuff about network attached storage in a virtualized environment, including NFS and iSCSI.
There was also a lot of stuff that got my brain stewing about future approaches both in our datacenter back-end stuff and in the regular office server rooms and even out on the floor. In particular, I think future shared storage that we buy will probably be moving away from fibre-channel and towards iSCSI, which is faster (when done right,) more flexible, and way cheaper. Also, I think that a lot more of our desktop workloads are virtualizable than we thought, and also we could probably achieve significantly higher hardware consolidation than we have been expecting.
The next year or two will probably see much more of our infrastructure becoming virtualized, that much is certain.
I’m at VMworld in San Francisco. Jenn’s here with me. I’ve already attended my first hands-on lab. It was about securing ESX Server. The lab was very well put together and the lab manual was very accurate. Well done, and I learned some useful stuff that we can put into practice right away.
I went on vacation with my family, starting with summer swimming provincials August 18, 19 and 20, up until September 2. In all that time the only writing I did was to send a few Facebook messages to family and update my Facebook profile. I’ve been back at work a week, and as usual I’m finding it slow to get back into the writing habit, both personally and professionally. I’m not sure why this is, but I’m guessing it’s just getting out of the writing habit. It doesn’t happen to me on long business trips, but that’s probably because I always blog during them. I have a big business trip coming next week, where I’m going to VMWorld in San Francisco. I imagine that will get me back into the writing habit, because there’ll be tons of interesting stuff to write about and I’m the only one from my work attending the conference so there’ll be no other real way of discussing what I’m learning.